Fuel economy analysis of a parallel hybrid bus using the optimal control theory

Distribution of the power between engine and motor is an important issue for parallel hybrid electric vehicles. A lot of studies have been carried out for the conventional passenger hybrid car's control logic. However, it still needs more studies for the parallel hybrid bus control logic. In this study, we developed a control logic based on the optimal control theory for the parallel hybrid bus. To verify the control logic, a forward simulator was developed. The control logic was applied to the forward simulator and the simulation was conducted. Backward simulation of which result is the global optimal was conducted for the comparisons of results from simulations. Consequently, similarity of forward and backward simulations was found.